CALGARY - Canada's newest and largest mosque opened Saturday, praised by Prime Minister Stephen Harper as an "architectural treasure."

Harper also strongly defended the Ahmadiyya community -- an offshoot Muslim sect persecuted in some countries -- for building a mosque that demonstrates "the true and benevolent face of Islam."

"This community knows first-hand what it is to experience persecution and discrimination based on your religious beliefs," he said following a tour of the sprawling mosque complex.

"So you understand at a profound level that promoting religious freedom is an essential building block for peace and stability here and throughout the world."

Harper and Opposition Leader Stephane Dion were among the hundreds who attended the opening. The group's global spiritual leader, Hadhrat Mirza Masroor Ahmad, was also there along with followers from around the world.

The prime minister praised the Ahmadiyya leader as a "courageous champion of religious freedom and of peace," and applauded him for denouncing anyone who perverts faith by using it as a justification for violence.

"However we define God, it is wrong to kill in his name," Harper said.

The mosque complex covers more than 4,300 square metres and includes a community centre, classrooms, office space, children's area, kitchen, dining room and a multi-purpose hall.

The main outward features are its massive steel dome together with a steel-capped minaret tower.

"It's a day of joy for us, tremendous joy, for the whole community," said Safeer Kahn, a spokesman for Calgary's Ahmadiyya community.

"There are hundreds of people who had this dream of having this big mosque for their use -- for their worship, for their social and educational activities. The dream came true today."

The mosque cost nearly $15 million to build with $8 million coming from local Calgarians. Ahmadiyya from all over Canada also chipped in.

"People sold their houses and children broke their piggy banks and actually this was a great example of sacrificing," Kahn said, adding the mosque complex will be open to everyone, whether they belong to Ahmadiyya or not.

"We welcome everyone here, and this mosque will be a symbol of peace. I assure you, Calgarians will be proud of having this building in their city."

Members of the Ahmadiyya faith, which began in India and now has millions of followers worldwide, call themselves Muslims and follow Islam's main tenets.

The Ahmadiyya believe that Muhammad was the final prophet. But they also believe Mirza Ghulam Ahmad was the Promised Messiah sent by Allah in the 19th Century to revive the teachings of Islam and reform the Muslim community.

Just last month, thousands of Indonesian Muslims took to the streets of Jakarta calling for the government to ban Ahmadiyya.

The faith is considered non-Muslim in Pakistan's constitution and some consider it heretical.

Kahn said the discrimination in other parts of the world is precisely why the Ahmadiyya are thriving in Canada, where religious freedom is tolerated.

"Anybody can have their own opinion and it does not affect us. We have our own goals and we do not believe in violent jihad and we believe that we are always open to discuss this issue.

"Religion is a personal matter and a person has the right to declare his religion so that's the right that Islam gave us."

Calgarian Imam Sayed Soharwardy, founder of Muslims Against Violence and the Islamic Supreme Council of Canada, said he respects the Ahmadiyya's right to religious freedom, but does not consider them to be Muslim.

"A lot of Muslims do not concede that they are Muslims," he said recently. "They pray like us, they fast, they do everything except this one particular belief.

"They are our Mormons. I call them our Mormons because the Mormons had Joseph Smith and they had Mr. Ahmad. Some people express hate about them, but in my book there is no word `hate.'"